The invention relates generally to the field of network communications. More specifically, the invention relates to a system and method for switching communications traffic at a node in a network.
Techniques for switching communications traffic at a node in a network are known. As illustrated in FIG. 1, a representative switch or router at a node in a network includes a chassis 150 populated by line cards 105, 110, 115, 120, 135, and 140, primary switch fabric card 125, back-up switch fabric card 130, and a controller card 145. Some known routers also use a back-up controller card (not shown).
The primary switch fabric card 125 and back-up switch fabric card 130 are configured to redirect network traffic (data) to one or more line cards. In turn, the line cards transmit the network traffic to a next or final destination node on the network. The primary switch fabric card 125 and back-up switch fabric card 130 can include, for example, crossbars or shared memory devices. The line cards 105, 110, 115, 120, 135, and 140 are used for buffering network traffic on either side of the switch fabric, and for performing other functions. Line cards typically serve both ingress and egress functions (i.e., for incoming and outgoing traffic, respectively).
Router communications can be separated into three categories: management plane control plane and data plane communications. The management plane is an interface between management functions external to the router (e.g., network servers or clients) and the router controller(s) for management of the router. For example, chassis configuration parameters that are derived from Service Level Agreements (SLA's) are communicated to the router on the management plane. The control plane uses local signaling protocols or other messages to control the resources of a router in accordance with the specified configuration. The data plane carries network data that is being redirected (or forwarded) by the router to the next or final destination node in the network.
In the data plane, network traffic is received at a line card, processed through the primary switch fabric card 125 (or back-up switch fabric card 130 if the primary switch fabric card 125 is not functioning), and forwarded to the (same or different) line card. The controller card 145 typically hosts switching application protocols (e.g., Open Shortest Path First (OSPF), Routing Information Protocol (RIP), Multi-Protocol Label Switching (MPLS) or other protocols) and generates messages to the line cards 105, 110, 115, 120, 135 and 140, the primary switch fabric card 125 and the back-up switch fabric card 130 in the control plane.
Known systems and methods for switching communications traffic have various disadvantageous. For example, in the control plane of known routers, a switching application must establish communications with each of the device drivers on line cards 105, 110, 115, 120, 135 and 140, the primary switch fabric card 125 and the back-up switch fabric card 130. Such a control scheme adds complexity to the development of switching applications. For example, where a line card becomes non-functional or is removed from the router chassis, the switching application must first identify the non-functional or removed card, then notify each of the device drivers associated with cards in chassis 150. Likewise, when a new card is added to chassis 150, the switching application must execute a lengthy process of registration, initialization, and configuration involving each of the device drivers. Including such complexities may extend the time-to-market for new switching applications under development.
Therefore, a need exists for a system and method to simplify the interface between a switching application and device drivers in the control plane of a network switch or router.